IRS P4 (OCEANSAT 1)

IRS P4 (OCEANSAT 1) is an active satellite operated by India, launched on 1999-05-26 from SRI. With over 27 years in orbit, it has far exceeded many satellites’ design lifetimes. It orbits in Low Earth Orbit (LEO) at altitudes between 706 km and 711 km with an inclination of 98.0°. It travels at approximately 27,013 km/h (7.50 km/s), completing one full orbit every 99 minutes — that’s roughly 14.55 orbits per day. Its near-polar, sun-synchronous orbit means it passes over any given point on Earth at approximately the same local solar time, ideal for consistent Earth observation lighting conditions. Its near-circular orbit (eccentricity close to zero) means it maintains a very consistent altitude throughout each revolution. At its current altitude, the estimated orbital lifetime before atmospheric re-entry is ~25–100 years. Orbital Radar tracks IRS P4 (OCEANSAT 1) in real time using the latest two-line element set (TLE) data, providing live position, altitude, speed and orbital path updated continuously.

IRS P4 (OCEANSAT 1) orbits at an average altitude of 709 km in a sun-synchronous orbit (SSO), a specialised subset of LEO where the orbital plane precesses to maintain a constant angle relative to the Sun. This provides consistent lighting conditions on every pass — essential for Earth observation, weather monitoring and environmental science. Within ±50 km of IRS P4 (OCEANSAT 1)’s average altitude, there are currently 255 active payloads and 1,543 tracked debris or rocket body fragments — notable neighbours include TERRA, AQUA, LANDSAT 9. With an inclination of 98.0°, IRS P4 (OCEANSAT 1) passes over latitudes between 98.0°N and 98.0°S, providing near-global coverage including the polar regions. Polar and near-polar orbits are used for reconnaissance, weather monitoring and Earth-observation missions that need to image every part of the planet. India operates approximately 108 active satellites in total, of which 6 share a similar altitude band with IRS P4 (OCEANSAT 1).